The A/C compressor on my 1987 Firebird stopped locking up so I checked the plug and there is no power going to the compressor, so it must be the A/C control relay. I have found pics of the relay itself but cannot see where it is located. If anyone can tell me where it is located that would be great. Thanks

 

 

please clarify

if you engage the A/C the compressor does not engage, is that correct? Do the cooling fans turn on? If so, go to the accumulator and on the low side port (faces the engine) stick a lil screwdriver in it for a second. Dpo you ge ta nice hiss or is it dead? If dead, you lost all of your freon for some reason namely a leak. If you have pressure, go to the other side of the accumulator and unplug the connector. jumper the connector together with a paper clip (it's a switch so don't worry) and try the A/C. Does it work? If so, either run without the switch or replace it

if that switch is bad, or there is no refrigerant in your system, it will be open and you won't get votage to the compressor

 

if there is no refrigerant ,does the compressor clutch have to be on when adding new refrigerant??, if so how do I make the clutch engage?

 

 

ok thanks

 

Always helpful info. I happen to be stuck. I have a '87 Camaro Sport Coup V-6 EFI, ~18 mo old A/C Compressor , just quit working last week. Followed the trouble shooting chain here,ended with no 12V @ the green wire @ the compressor. Jumped 12V to it and the compressor engaged and started to cool the cabin.

I presume checking the A/C relay is the next step. Im confused as to where it is on the car?? Any tips?

Thanks in advance

 

Engine compartment Relay placement

Driver's side firewall near fender for '87 Sport Coupe V6 EFI

 

I answered my own question , my manual (publisher shall remain unnamed) has a lot of useful info , unfortunately its not indexed in a user friendly way . I think this diagram was in the emissions section. I attached the diagram and a actual picture of the relay placement in this thread, it might be useful to somebody.

Back to the problem at hand, I removed the A/C relay, put a mild 12V across the primary (coil) and the relay clicked on and off as you would expect it to . I put it back in the car and turned A/C to on and the relay didn't turn on. There is 12V (see relay diagram below) @ pins 3 and 1 (Im guessing somehow there is a open from the lever on the dash and pin 4) If anybody has any suggestions let me know . Thanks (Ref '87 Sport Coupe V-6 EFI) I'll try to post a diagram of the relay in a separate post.

 

I'd get a set of gauges on it to see if you have enough low pressure to activate the low pressure side. I don't think it will come on if you don't have enough refrigerant

 

Thanks, Ive already shorted the pressure switch connector on the low side and the compressor didn't click on (although the engine revED like it should of ) . The system has pressure (and wont take anymore refrigerant ) and cooled down easily once I jumped the compressor strait to 12V . The site wouldn't let me post the page with the relay diagram. However the "stamp number" is 10094701. There are plenty of pics on line.

 

OK, with that said yeah, you may have a problem with the HVAC selector head inside the car

 

Thanks! That was my thought as well. (unfortunately another under the dash adventure....)

 

Wow, problem solved! For the sake of brevity, i didn't mention that I noticed a few other things occurring on or about the same time the A/C quit working. The car seemed to run a bit rougher, the ignition buzzer would come on when the car was running and the lights were on (making a night drive a ear-ache) and it acted like it was running richer ( I could smell the faint odor of fuel) . Today while I was driving it I noticed the idiot lights didn't come on as they normally do when you turn the ignition on, and the gas gauge acted like it was disabled. The Engineer in me doesn't believe in coincidence, so I checked the "Gauges" 10A fuse (#9) and it was blown. I just replaced it, started the car and all things (except the buzzer which I removed this week) were witnessed to be working, the A/C kicked on as it should. That "Gauges" fuse must also gate the AC lever /switch on the dash panel(if I can ever get a accurate schematic I'll have to study how that works) . Hopefully my toil here will save somebody a days work on a similar problem. Happy Trails!

 

To justify results at least for a/c (for v6)..

 

Thank you ! I'll print that for my file.